Various methods have been proposed for causing separate light fixtures to emit time-changing modulation of light (e.g., color and/or intensity) in a synchronized fashion so that all the fixtures emit the same color-modulated or intensity-modulated light together. “Synchronization” or its variants means, in this specification and claims, synchronization of an optical filter wheel in space (position or orientation), time (simultaneity), and speed (angular rate of rotation).
One prior art method involves the steps of moving the optical filter wheels of multiple light fixtures to a home position after a trigger event, such as application of power to a light fixture. After a brief period of time during which all optical filter wheels are simultaneously at their home positions, all optical filter wheels are then rotated in synchrony by coordinating to a similar time reference. It would be desirable to provide a more sophisticated method for synchronizing optical filter wheels that avoids simultaneously placing all filters wheels at their home positions in the foregoing manner.
The following parts of this Background of the Invention describe various features required for making an optical filter wheel of a light fixture synchronizable with optical filter wheels of other light fixtures.
A “light fixture” in this specification and claims means either a fixture containing a light source that provides light to a target region to be illuminated either with the use of a fiberoptic light cable, or without the use of a fiberoptic light cable. Further, an optical filter wheel could contain segments that modify either the amplitude, or color spectrum, of transmitted light in some useful fashion. For modifying the color spectrum of light, optical filter wheels are typically, but not always, constructed of dichroic color filter segments.
A typical optical filter that only modifies the color of light, but not its intensity, is often referred to as, simply, a color wheel.